After several manual Nvidia driver installations folder C:\Program Files\NVIDIA Corporation\Installer2 grew up to 2.7 Gb
Judging by subfolders date it contains all the previous versions of drivers data.
I suppose removing all the folders except the ones with the latest date should be safe. Except InstallerCore folder - it has old date, but new files.
Or maybe remove all the files with the old date and then remove all empty folders.
There's several Nvidia cleaners in the community winapp2.ini file. If none of them clean that folder perhaps post in the winapp2.ini topic and maybe someone will make a cleaner including that folder -- if it's safe to clean.
with install the new nvidia driver you can mark the choose box "new installation and delete nvidia remains"
after a few installations on my windows a have no driver-remains in this folder...
- ofcourse, with this install-option go all personal settings lost.